1. Field of the Invention
The present invention relates to a process for producing a phenol from a benzene.
2. Description of the Related Art
Already known are a process for producing cyclohexenes by a partial hydrogenation of benzenes in the liquid phase, a process for producing oxygen-containing compounds of cyclohexenes such as cyclohexanones, cyclohexenones, and cyclohexenols by an oxidation of cyclohexenes with molecular oxygen, a process for producing cyclohexanols by a hydration of cyclohexenes, and a process for producing phenols by a dehydrogenation of cyclohexanones or cyclohexanols. Also known are a process for converting cyclohexanes into benzenes by dehydrogenation, and a process for separating benzenes, cyclohexenes, and cyclohexanes.
Processes for producing cyclohexenes by a partial hydrogenation of benzenes in the liquid phase are disclosed in, for example, Japanese Unexamined Patent Publications (Kokai) No. 48-36150, No. 53-46938, No. 57-130926, No. 59-155328, No. 60-184031, No. 60-202829, No. 61-122231 and No. 62-45544. According to the process of Japanese Unexamined Patent Publication (Kokai) No. 62-45544, for example, cyclohexenes can be obtained by a partial hydrogenation of benzenes in the presence of zinc sulfate by using a catalyst obtained by a reduction of Ru compounds containing Zn compounds with hydrogen.
Processes for producing oxygen-containing compounds by an oxidation of cyclohexenes with molecular oxygen are disclosed in, for example, J.O.C., Vol. 34, No. 12, P 3949-3952 (1969), J.C.S., Chem. Comm., P 1274-1275 (1981), and Acta Chimica Hungarica 122 (2), P 175-180 (1980). According to the process disclosed in Acta Chimica Hungarica 122 (2), p 175 (1986), for example, cyclohexanones can be obtained by an oxidation of cyclohexenes with molecular oxygen by using copper ketenide (Cu.sub.2 C.sub.2 O) as the catalyst.
Processes for producing cyclohexanols by a hydration of cyclohexenes are disclosed in Japanese Patent Publications (Kokoku) No. 38-15619, No. 43-8104, Japanese Unexamined Patent Publications (Kokai) No. 59-193836, No. 61-293939, Journal of Petroleum Society of Japan, 28 (2), P 172-5, Japanese Unexamined Patent Publications (Kokai) No. 61-221141 and No. 62-120333. According to the process of Japanese Unexamined Patent Publication (Kokai) No. 61-293939, for example, cyclohexanols can be produced by a hydration of cyclohexenes in the liquid phase in the presence of a molybdenum compound, by using p-toluenesulfonic acid as the catalyst.
A process for producing phenols by a dehydrogenation of cyclohexanones or cyclohexanols is disclosed in, for example, Japanese Patent Publication (Kokoku) No. 44-6810. According to this process, phenols can be produced by a dehydrogenation of cyclohexanones or cyclohexanols under gas phase reaction conditions by using a platinum compound as the catalyst.
Processes for producing benzenes from cyclohexanes are widely known, as disclosed in, for example, U.S. Pat. No. 3,326,994, U.S. Pat. No. 4,366,091, U.S. Pat. No. 4,083,883. According to the process of U.S. Pat. No. 4,083,883, benzenes can be produced by a dehydrogenation of cyclohexanes under gas phase reaction conditions by using a catalyst comprising a combination of platinum, rhodium, and nickel carried on alumina.
Processes for separating benzenes, cyclohexenes, and cyclohexanes are disclosed in, for example, Japanese Unexamined Patent Publications (Kokai) No. 51-127043, No. 58-172323, No. 56-95130, No. 56-95127, No. 58-164524, and No. 58-164525. According to the process of Japanese Unexamined Patent Publication (Kokai) No. 51-127043, for example, the respective components can be separated with a good yield by an extraction distillation, using dimethyl sulfoxide as the solvent.
As described above, processes for the production of cyclohexenes, processes for the production of cyclohexanones, cyclohexenones, and cyclohexanols, and processes for the production of phenols by a dehydrogenation of cyclohexanones or cyclohexanols are known, but a process for the production of phenols from benzenes by using hydrogen as a mediating agent is not known.